Welcome to our tutorial on the 4C's!
During the course of this tutorial I will be famialiarizing you with 2 grading systems. The GIA (Gemological Institute of America) Diamond Grading System is perhaps the most traditional and well known throughout the world and we will also be discussing elements of the AGS (American Gemological Society) Diamond Grading system as well. Both labs offer a complete grading system and analysis of the 4 C's which we will be examining in quite some detail in the following chapters. While there are many gem labs throughout the world and some that are as reputable, these 2 labs, in my professional opinion, represent the most conservative labs. Meaning they have the best interests of the consumer in mind. With the many tools available for diamond grading it is easy to check the grading consistency of any lab once one has the proper education and equipment.
For the years I've been purchasing diamonds, I can always determine if the stone is worth what I'm paying for it by performing a few tests on it. A lot of consumers think that this is all standard procedure by people who sell diamonds. This is not so and most jewelers don't have half the tools they should for properly grading a diamond.
The first thing we do is weigh it on a scale to determine the carat weight.
Next I'll check it out under a gemological microscope for imperfections. I want to see how clear the stone is, or it's "clarity". Most stores at best offer a loupe. As you progress through this site you'll see how a scope can spoil ya.
Then I'll lay the diamond upside down (point up) against a flat white background (like a white business card) and see if there is any "color" in the stone (most typically yellow or brown) and determine the intensity or saturation of the color that is in the stone, after observing this I also put the diamond in something called a colorimeter to further refine the color grade. (You'll learn more about the colorimeter as you get to the chapter on "color").
I'll then take the diamond and put it into a device called a "proportion analyzer" (Sarin Machine) to determine how well the diamond cutter did his job when "cutting" the stone. Sadly, the most information a jewelry store can tell you about the cut is that "it's a round cut", or "it's a pear cut", or "the cut is good". When you get done with this site these comments from jewelers will make you laugh. ;) and add new dimension to what exactly is a good cut stone. I'll be addressing the most popular cut grading system used amongst gemologist's today. The AGS cut grading system.
A very new device I've recently put together is called the LightScope. For years I've taught my clients about how light can leak out of poorly cut stones and how brilliant diamonds can be when cut properly. This instrument, the LightScope, graphically displays the amount of light leakage a diamond has as well as it's light retention. You'll learn about that exclusively here at "The Ultimate Diamond Information Site".
These 4 aspects of the diamond that are considered are known as the "Four C's" of diamonds. If any of you has done any kind of reading or research at all on diamonds, you have, no doubt heard this term, "The Four C's". The Institute that devised this diamond grading system is the Gemological Institute of America (heretofore referred to as GIA).
While there are many excellent Gemological Institutions throughout the world, this one is probably the most recognized. On this site you are going to learn many things about the 4 C's that is simply not found elsewhere on the Web. So kick back, get a cup of java and get ready to have fun learning about one of God's most incredible creations.
Click here to proceed to our next chapter: New Cut Grading.